Add type cast definitions for CPDF_Stream.

fpdfsdk/src/fpdfppo.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../../public/fpdf_ppo.h"
 #include "../../third_party/base/nonstd_unique_ptr.h"
 #include "../include/fsdk_define.h"
 
@@ skipping 229 matching lines @@
       for (FX_DWORD i = 0; i < count; ++i) {
         CPDF_Object* pNextObj = pArray->GetElement(i);
         if (!pNextObj)
           return FALSE;
         if (!UpdateReference(pNextObj, pDoc, pObjNumberMap))
           return FALSE;
       }
       break;
     }
     case PDFOBJ_STREAM: {
-      CPDF_Stream* pStream = (CPDF_Stream*)pObj;
+      CPDF_Stream* pStream = pObj->AsStream();
       CPDF_Dictionary* pDict = pStream->GetDict();
       if (pDict) {
         if (!UpdateReference(pDict, pDoc, pObjNumberMap))
           return FALSE;
       } else {
         return FALSE;
       }
       break;
     }
     default:
@@ skipping 141 matching lines @@
   if (!pSrcDict)
     return FALSE;
 
   CPDF_Dictionary* pDstDict = pDstDoc->GetRoot();
   if (!pDstDict)
     return FALSE;
 
   pDstDict->SetAt(FX_BSTRC("ViewerPreferences"), pSrcDict->Clone(TRUE));
   return TRUE;
 }